On Tue, Dec 03, 2019 at 01:03:04PM +0100, Greg KH wrote: > On Tue, Dec 03, 2019 at 12:44:15PM +0530, Amol Grover wrote: > > On Tue, Dec 03, 2019 at 07:40:52AM +0100, Greg KH wrote: > > > On Tue, Dec 03, 2019 at 11:55:03AM +0530, Amol Grover wrote: > > > > Compiled, Booted, however I'm getting the following errors when running > > > > "make kselftest" > > > > > > > > sudo dmesg -l alert > > > > > > > > [34381.903893] BUG: kernel NULL pointer dereference, address: 0000000000000008 > > > > [34381.903904] #PF: supervisor read access in kernel mode > > > > [34381.903908] #PF: error_code(0x0000) - not-present page > > > > > > Which test causes this problem? > > > > IIRC I didn't run make kselftest with summary=1 option. Is there any > > other way to get that information? The logs that kselftest generated > > also don't seem to help in this. > > Watch the output when you run this? I don't know, try re-running it > with that option. > I did. The tls test under tools/testing/selftests/net seems to be the culprit. More information below. > > > ANd is it new in 5.3.13? > > > > > > > I previously ran kselftest on 5.4-rc7 and 5.3.9 (default kernel shipped > > by openSUSE), both were fine. However, a bit of backstory: > > > > A day ago I used kselftest from the linux/next branch and ran it (w/o > > sudo). It showed me the exact same error. However, I was running a > > modified version of 5.3.13, but those modifications were actually > > trivial (5 lines changed) and shouldn't have resulted in this kernel > > error. So, I switched to the vanilla 5.3.13 and ran kselftest (w/o sudo) > > again. I ran it 3 times (w/o any errors), switched back to the modified > > kernel and ran kselftest (w/o root) 2 more times and everything was > > fine. Then I decided to test the vanilla one again for the 4th time, but > > this time I ran kselftest as root where this BUG popped again. > > Try a kernel.org 5.3.9 and if that works, then try 5.3.13 and if that > fails, run 'git bisect' and try to find the offending kernel commit. > After finding the test that was resulting in the BUG, I decided to check again against 5.3.13 (= BUG). I had recently compiled 5.4.1 as well so I decided to run this test against 5.4.1 (= BUG). After this I realized I had 5.3.9 kernel kept away so I decided to run the test against that too (= BUG). After 5.3.9's error something didn't feel right. Mind you I was using kselftest from linux/next so I got suspicious about the test it-self. I ran kselftest from 5.4.1 on kernels 5.4.1 and 5.3.13 and none of them resulted in the BUG this time. After a bit of digging I found out the next branch had 2 additional test cases for the tls test, and one of them (sendmsg_fragmented) is the actual culprit that was causing all this. TL;DR: tools/testing/selftests/net/tls.ci:sendmsg_fragmented from the next tree appears to be broken(?) Thanks Amol > thanks, > > greg k-h
